Specifications: Type: wireless doorbell Colour: black Material: plastic Voltage of plug-in receiver: 110-260V / 50-60Hz Transmitter battery: 1 x 12V 23A alkaline battery (integrated) Ringing tone: 55 melodies (optional) Wireless distance: 300M outdoors Sound Voltage: 5 levels, 0-110dB Silent mode: support Transmitter waterproof level: IP55-Operating frequency: 433.92MHz 280KHz Working temperature: -30 ~ + 70 Size (receiver): approx. 8.2x8.2x2.4 cm/3.2x3.2x3.2x0.94 inches (L x W x H). Size (transmitter): approx. 3.3x1.6x7.3 cm/1.25x0.63x2.87 inches (length x width x height). Features: Long wireless range With a maximum working range of 0-300m in open spaces, you won't miss any visitors even if you are in some rooms. Waterproof IP55 waterproof doorbell button can work even in harshest weather conditions such as storms, direct sun exposure and frost. CE, FCC, ROHS, PSE, TELEC. CERTIFIED. Easy installation The easy to install button sticks well to any surface or Use the screws to secure the button to the door frame, simply plug it in and it is ready to use. No battery is required for the receiver. The bells also illuminate blue lights, so even with headphones on they are visible. Easy programming Multifunctional. There are 55 chime tones with 5-level volume adjustment (silent mode) for options to deliver rich and clear sound. Package includes:1 x wireless doorbell1 x receivers Note:-Allow small errors due to manual measurement. Thank you for your understanding. Monitors are not calibrated in the same way, the colour of the item shown in the pictures may look slightly different from the real thing. Please take the real one as standard.